• A comprehensive source for world-wide available medical expert and knowledge-based systems - It provides information for physicians, students, and other health-care professionals on over 65 state-of-the-art medical expert and knowledge-based systems. Physicians are provided with a detailed description of the programs, links to online versions, information about pricing and availability, clinical use, information about the developer, contact addresses, and evalution statistics—giving physicians the opportunity to get fast and easy access to the specific knowledge they are looking for.
  
  
• TheraDoc, Inc.™ is a medical informatics company that designs, markets and implements expert systems for clinical decision support.
  
  
• VisualDx - is an image-based software system that serves as a reference to support diagnosis and treatment.
  
  
• DXplain
  A decision support system which uses a set of clinical findings (signs, symptoms, laboratory data) to produce a ranked list of diagnoses which might explain (or be associated with) the clinical manifestations. DXplain provides justification for why each of these diseases might be considered, suggests what further clinical information would be useful to collect for each disease, and lists what clinical manifestations, if any, would be unusual or atypical for each of the specific diseases.
  
  
• QMR - Quick Medical Reference
  QMR is a diagnostic decision-support system with a knowledge base of diseases, diagnoses, findings, disease associations and lab information. With information from the primary medical literature on almost 700 diseases and more than 5,000 symptoms, signs, and labs, Iliad can suggest relevant diagnoses, give advise regarding cost-effective workup strategies, and explain relationships of findings to diseases. (click here to read a well-done training and support guide)
  
  
• HDP, the Heart Disease Program
  The Heart Disease Program (formerly known as the Heart Failure Program) is a program to assist physicians with the diagnosis of cardiovascular disease.
  
  
• PRODIGY (Prescribing RatiOnally with Decision Support In General Practice studY)
  PRODIGY is a major initiative in the United Kingdom to develop and evaluate a computerised prescribing decision support system for UK General Practice. PRODIGY is based at the Sowerby Centre for Health Informatics at Newcastle (SCHIN) and is funded by the NHS Executive.
  
  
• AIDEDIAG - Programme d'aide au diagnostic et de formation médicale continue (FMC) Note: An english version is planned.
  
  
• DiagnosisPro - The database now has 9,000 disease/drug terms and 16,000 attributes (symptoms, signs, lab,
  xray findings)---linked with 120,000 relationships. Suggested treatment options are now
  included, as well.
  
  
• Problem Knowledge Couplers - Problem Knowledge Couplers are data capture and clinical guidance software tools that provide decision and management support to clinicians.
  
  
• Iliad - medical expert software that provides expert diagnostic consultations and patient simulations. Version 4.5 covers more than 930 diseases and 1500 syndromes and provides treatment protocols for each including the ICD-9 codes for each diagnosis. There are 13,900 disease manifestations.
  

For an excellent evaluation of 4 commercially available decision support systems see: 
(Berner ES, Webster GD, Shugerman AA, Jackson JR, Algina J, Baker AL, Ball EV, Cobbs CG, Dennis VW, Frenkel EP, et al. Performance of four computer-based diagnostic systems. N Engl J Med 1994 Jun 23;330(25):1792-6 ). 
They found that "on average, less than half the diagnoses on the experts' original list of reasonable diagnoses were suggested by any of the programs. However, each program suggested an average of approximately two additional diagnoses per case that the experts found relevant but had not originally considered."


For an comprehensive review of published reports of medical diagnostic decision support systems from 1954-1993 see
Miller RA. Medical diagnostic decision support systems--past, present, and future: a threaded bibliography and brief commentary. J Am Med Inform Assoc 1994 Jan-Feb;1(1):8-27
Published erratum appears in J Am Med Inform Assoc 1994 Mar-Apr;1(2):160

For an editorial on Clinical decision support systems see: Classen, DC. Clinical Decision Support Systems to Improve
Clinical Practice and Quality of Care (Editorial) J Amer Med Assoc. October 21, 1998

For a new text on the subject see: Clinical Decision Support Systems in Theory and Practice by E.S. Berner, University of Alabama at Birmingham, Birmingham, AL (Ed.) ( click to purchase from Amazon.com) 
This book is designed to be 1) a resource book on diagnostic systems for informatics specialists; 2) a textbook for teachers or students in health or medical informatics training programs; and 3) a comprehensive introduction for clinicians, with or without expertise in the applications of computers in medicine, who are interested in learning about current developments in computer-based diagnostic systems.